/*
 * Created on Jun 17, 2005
 * Created by Alon Rohter
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.azureus.core.peermanager.messaging;

import java.util.Map;

import org.gudy.azureus2.core3.util.BDecoder;
import org.gudy.azureus2.core3.util.BEncoder;
import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.core3.util.DirectByteBuffer;
import org.gudy.azureus2.core3.util.DirectByteBufferPool;

public class MessagingUtil {

    /**
     * Convert the given message payload map to a bencoded byte stream.
     * 
     * @param payload
     *            to convert
     * @return bencoded serialization
     */
    public static DirectByteBuffer convertPayloadToBencodedByteStream(Map payload, byte alloc_id) {
        byte[] raw_payload;

        try {
            raw_payload = BEncoder.encode(payload);

            if (raw_payload == null || raw_payload.length == 0) {

                throw (new Exception("Encoding failed"));
            }
        } catch (Throwable t) {
            System.err.println("Payload encoding failed: " + payload);
            Debug.out(t);
            raw_payload = new byte[0];
        }

        DirectByteBuffer buffer = DirectByteBufferPool.getBuffer(alloc_id, raw_payload.length);
        buffer.put(DirectByteBuffer.SS_MSG, raw_payload);
        buffer.flip(DirectByteBuffer.SS_MSG);

        return buffer;
    }

    /**
     * Convert the given bencoded byte stream into a message map.
     * 
     * @param stream
     *            to convert
     * @param min_size
     *            of stream
     * @param id
     *            of message
     * @return mapped deserialization
     * @throws MessageException
     *             on convertion error NOTE: Does not auto-return given direct buffer on thrown exception.
     */
    public static Map convertBencodedByteStreamToPayload(DirectByteBuffer stream, int min_size, String id) throws MessageException {
        if (stream == null) {
            throw new MessageException("[" + id + "] decode error: stream == null");
        }

        if (stream.remaining(DirectByteBuffer.SS_MSG) < min_size) {
            throw new MessageException("[" + id + "] decode error: stream.remaining[" + stream.remaining(DirectByteBuffer.SS_MSG) + "] < "
                    + min_size);
        }

        byte[] raw = new byte[stream.remaining(DirectByteBuffer.SS_MSG)];

        stream.get(DirectByteBuffer.SS_MSG, raw);

        try {
            Map result = BDecoder.decode(raw);

            stream.returnToPool();

            return (result);

        } catch (Throwable t) {
            throw new MessageException("[" + id + "] payload stream b-decode error: " + t.getMessage());
        }
    }

}
